Brake apparatus with blind cable installing means

ABSTRACT

A parking brake assembly of the blind-cable-connection type including a backing plate containing an opening, a helical guide spring arranged to guide a flexible resilient inner cable member toward a ramp surface on a parking brake lever for the blind connection to the inner cable member to the lever, characterized in that the angle of inclination of the ramp surface relative to the cable axis is contained in a plane that is both parallel with the longitudinal axis of the lever and that is inclined at an acute angle relative to the axis of the inner cable member. This construction permits the parking brake lever to be simply and economically formed from a blank of flat metal stock, the cable-retaining slot being defined by a slot contained between bifurcated portions of the ramp surface. The helical guide spring includes portions having tightly wound turns, thereby to assist in connecting the spring with the backing plate and/or with the parking brake lever.

REFERENCE TO RELATED APPLICATION

This application is a continuation of the prior Boyer et al applicationSer. No. 275,390 filed Nov. 23, 1988 now U.S. Pat. No. 4,872,533.

STATEMENT OF THE INVENTION

This invention relates to an improved parking brake arrangement of theblind cable installation type including improved ramp means forautomatically connecting the inner brake cable member with the parkingbrake lever, characterized in that the angle of inclination of the rampsurface is contained in a plane that is normal to the plane of the leverand which contains the axis of the cable member, whereby the parkingbrake lever may be simply and economically fabricated from a blank offlat metal stock, and which affords simple assembly and disassembly ofthe parking brake cable. Use is made also of a helical guide springhaving portions of tightly wound turns, so arranged as to improve theconnection of the spring with the backing plate and/or with the parkingbrake lever.

BRIEF DESCRIPTION OF THE PRIOR ART

In the prior Jaksic patent No. 4,753,325, a parking brake assembly isdisclosed in which blind cable connecting means are provided forconnecting a flexible resilient parking brake cable with a parking brakelever, use being made of a helical guide spring for guiding the cabletoward an inclined ramp surface on the lever. As the extremity of thecable end progressively rides up the ramp surface during insertion ofthe inner cable member via the guide spring, a position is reached inwhich the cable extremity extends through an opening in the rampsurface, whereby the cable is introduced into a retaining slot toautomatically connected the cable end with the lever. In this Knownconstruction, the fabrication of the ramp portion of the lever is rathercomplex and requires a number of manufacturing steps, owing to theprovision of a rather unique slot configuration in the ramp surface, andthe requirement for a curved wall surface with a retaining lip extremityfor maintaining the cable extremity in line during the blind assembly ofthe parking brake cable. Thus, the manufacture of the parking brakelever requires a relatively large number of manufacturing steps, therebyincreasing the resulting cost of the lever. Furthermore, owing to theprovision of the aforementioned curved wall with the overhangingretaining lip, disassembly of the cable member from the lever is mostawkward and difficult to achieve.

The present invention was developed to avoid the above and otherdrawbacks of the known blind parking brake assembly, and to provide animproved construction in which the parking brake lever is easily andeconomically fabricated from a blank of flat metal stock.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide an improvedparking brake assembly of the blind cable connection type in which theparking brake lever is formed from a blank of flat metal stock andincludes an inclined ramp surface contained in a plane that is parallelwith the axis of the lever and inclined at an acute angle relative tothe axis of the cable, the ramp being bifurcated in a simple manner todefine a slot that receives the cable member when in the connectioncondition. A pair of cooperating semi-circular arms integral with thelever define a generally annular spring support portion spaced forwardlyof the ramp surface, which support portion receives one end of the guidespring.

According to another object of the ivention, the guide spring includesportions of compacted tightly-wound coil turns for improving theconnection of the spring to the lever and/or the backing plate. In oneembodiment, the tightly wound turns are provided at the ends of thespring. Thus, the turns of the spring portion that extend through theopening in the backing plate are tightly wound to prevent lateralmovement of the spring relative to the opening. At the other end, thetightly wound turns enhance the entry of the spring end into thegenerally annular spring support portion of the lever. In a secondspring embodiment, the tightly wound turns define bell-shaped portionsof enlarged outer diameter spaced from the associated spring ends. Thus,one bell-shaped portion limits the extend of outward travel of thespring relative to the backing plate opening in which the spring ismounted, and the other bell-shaped portion limits the extent to whichthe spring enters the annular spring support portion of the lever.

A further object of the invention is to provide a lever constructionhaving the aforementioned bifurcated ramp structure, whereby theflexible parking brake cable member may be readily connected anddisconnected from the lever.

According to another object of the invention, the lever is fabricatedfrom a blank of flat metal stock by a limited number of simple pressing,forming and machining steps, thereby reducing the cost of the lever.According to the preferred embodiment, the annular spring supportportion on the lever is formed from two oppositely extending tabs thatare rolled to define cooperating semi-circular arms. In order to limitmovement of the spring end relative to this spring support portion, thesemi-circular arms may be provided with radially inwardly extending tabsthat serve as stops for the springs.

According to a further feature of the invention, the ramp portion of thelever includes an integral extension arranged to abut the associatedbrake shoe during the blind assembly of the cable to the ramp portion,thereby spacing the ramp portion from the shoe to a sufficient extent topermit the cable extremity to ride over the peak of the ramp and topermit entry of the cable member into the retaining slot contained inthe ramp.

Still another object of the invention is to provide a blind entry cableinstallation arrangement in which the manufacturer is permitted tocompletely assemble the brake assemblies and drums to the axle housingmember at one location and to install the flexible cable member atanother time or location, thereby virtually eliminating the possibilityof damaging parts and eliminating the need for costly and time consumingreworking to remove and replace the damaged parts, resulting in aconsiderable cost savings to the manufacturer.

A further object of the invention is to provide a mechanical brakeactuating lever means that is simple and economical to manufacture andassemble and that is readily adaptable to a variety of brake type andsize applications.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention will become apparent froma study of the following specification, when viewed in the light of theaccompanying drawings, in which:

FIG. 1 is a perspective front view of a modification of the prior artparking brake apparatus with blind cable connecting means.

FIG. 2 is a front elevational view of the parking brake lever of FIG. 1;

FIG. 3 is a detailed right side view of the lever taken along line 3--3of FIG. 1;

FIG. 4 is a sectional view taken along line 4--4 of FIG. 2;

FIG. 5a-5f are detailed front elevational views, with certain partsbroken away for clarity, illustrating the manner of blind cableconnection of the flexible inner brake cable member with the lever ofFIGS. 1-4;

FIG. 6 is a perspective front view of the improved parking brakeassembly of the present invention;

FIGS. 7 and 8 are front elevation and right side views, respectively, ofthe parking brake lever of FIG. 6;

FIG. 9 is a sectional view taken along line 9--9 of FIG. 7;

FIGS. 10a-10j are detailed elevation and corresponding sectional viewsrespectively, illustrating the blind cable connection of the inner brakecable member to the lever of FIG. 6;

FIG. 11 is a perspective view of a modified second embodiment of theimproved parking brake apparatus of the present invention as applied toone rear wheel of the vehicle;

FIG. 12 is a front elevational view of a reversed modification of thelever of FIG. 11 as adapted for use with the other rear wheel of thevehicle, and FIGS. 13 and 14 are sectional views taken along lines13--13 and 14--14 of FIG. 12, respectively;

FIGS. 15a-15j are detailed elevation and companion sectional viewsrespectively, illustrating the blind cable connection of the inner brakecable member to the lever of FIG. 11;

FIGS. 16 and 17 illustrate parking brake lever and cable assembliesincluding first and second guide spring embodiments, respectively;

FIG. 18 illustrates a third guide spring embodiment arranged between abacking plate and the associated parking brake lever; and

FIGS. 19-21 illustrate the manner in which the guide spring islongitudinally compressed during the connection to the backing plate ofa self-connecting fitting on an outer conduit member.

DETAILED DESCRIPTION

Referring first more particularly to FIGS. 1-4, the brake apparatus fora vehicle includes a stationary backing plate 2 to which are connected apair of brake shoes 4 and 6 that are operable by a conventional brakecylinder 8. Arranged between the brake shoes is a rigid strut element10, and conventional threaded adjusting means 12 are connected with thebrake shoes on the opposite side of the strut member from the brakecylinder 8. A parking brake lever 14 is pivotally mounted on the strutmember 10 for operating the brake shoes toward a locked condition, saidparking brake lever being pivotally operable about pivot axis 15 by theinner cable member 16 of a parking brake cable assembly including anouter conduit member 18. The inner cable member extends longitudinallythrough a helical guide spring 20 that extends at one end through anopening contained in the backing plate 2, and the other end of thespring being connected with a transversely arranged spring supportportion 14a integral with the parking brake lever 14. Spaced from thespring support portion 14a is a ramp portion 14b including an inclinedramp wall 14c having a ramp surface that extends at an acute angle α tothe axis of the spring support portion 14a, as shown in FIG. 2, saidramp surface also being inclined at an acute angle by the complementaryangle β to the longitudinal axis of lever 14. Thus, as shown in FIG. 4,the ramp portion 14b has a generally U-shaped cross-sectionalconfiguration and includes a ramp wall 14c which contains a verticalslot 24 that receives the inner cable member 16 when the cable isconnected with the ramp portion 14b, as will described below.

Referring now to FIGS. 5a-5f, to connect the inner cable member with thelever 14, the enlarged extremity 16a of the inner cable member 16 isprogressively introduced via the guide spring 20 until it passes throughthe annular spring support portion 14a of the lever 14 as shown in FIG.5a. When the rounded extremity of the inner cable member 16 engages theramp wall surface 14c as shown in FIG. 5b, the extremity 16a is guidedup the ramp surface 14c as shown in FIGS. 5b and 5c. When the cableextremity 16a enters the enlarged upper end of slot 24 as shown in FIG.5d, the enlarged portion 16a rides over the corresponding edge of theslot and the cable, owing to its inherent resiliency, returns to itsoriginal linear configuration as shown in FIGS. 5e and 5f, whereupon theenlarged extremity 16a seats in a corresponding recess contained in theramp portion 14b, thereby to lock the inner cable member 16 with thelever 14, as shown in FIG. 5f. Following connection of the inner cablemember to the lever, tensioning of the cable causes lever 14 to pivot inthe clockwise direction about the pivot axis 14 defined by the strut 10,thereby to displace the brake shoes outwardly toward positions inlocking engagement with the associated brake drum.

As shown in FIGS. 5b-5f, the end extremity 16a of the inner cable memberis contained between the parallel surfaces of the tab portion 14b andthe lever 14 as the cable is displaced toward the locked condition shownin FIG. 5f, and therefore the inner cable member is relativelyinaccessible in the event it should be wished to disassemble the samefrom the parking brake lever 14. The lever 14 is preferably fabricatedfrom a blank of flat metal stock, a relatively large number of foldingand pressing steps being required to form the slotted ramp portion 14 ofthe lever. Furthermore, the generally annular spring support portion 14ais formed by bending a single tab member into a generally circularconfiguration, thereby to define an axial opening for receiving thecorresponding end of the helical guide spring 20.

Referring now to FIGS. 6-9, the improved parking brake apparatus of thepresent invention includes an improved parking brake lever 114 that ispressed and formed from a blank of flat metal stock and includes at oneend a generally annular spring support portion 114a, and a ramp portion114`b. The transversely arranged annular spring support portion 114aincludes a pair of integral arm portions 114g and 114h (FIG. 8) that arebent to define cooperating semi-circular configurations, thereby todefine a generally annular opening for receiving the associated end ofthe helical guide spring 120. The ramp wall surface 114c has an angle ofinclination α' relative to the axis of the spring support portion 114a,as shown in FIG. 9, said ramp surface being contained in a planegenerally parallel with the longitudinal axis of lever 114. This rampwall 14c is bifurcated by means of a simple slot opening 140 thatextends downwardly from the upper edge of the ramp wall 114c.

In accordance with an important feature of this embodiment, the rampportion 114b includes an extension 114f that extends outwardly from theright hand side of the lever as shown in FIGS. 7 and 10a thereby toengage the associated brake shoe 106 to space the ramp wall 114c fromthe brake shoe and to permit the connection of the inner brake cablemember 116 to the lever 114. More particularly, as the inner brake cableis progressively introduced through the end portion of the helical.guide spring 120, though the opening 122 in the backing plate, throughthe guide spring 120, and through the spring support portion 114`a, theenlarged extremity 116a engages the ramp surface 114c, as shown in FIGS.10c and 10d, whereupon the rounded extremity 116a rides up the rampsurface 114c, as shown in FIGS. 10e and 10f. Further insertion of theinner cable member 116 causes the enlarged portion 116a to ride over theupper edge of the ramp wall 114 (FIGS. 10g and 10h), whereupon the innercable member 116 is laterally displaced downwardly through the slot 140to the position of FIGS. 10i and 10j, whereupon the enlarged headportion 116a reaches a seated position behind the bifurcated rampportion 114c, and is retained in this position as shown in FIG. 10j. Theinner cable member is now connected with the parking brake lever 114,whereupon tensioning of the inner cable member 116 causes pivtalmovement of the lever 114 to lock the brake shoes against the associateddrum.

It is important to note that in the improved embodiment of FIGS. 6-10,the inner cable member may be readily disassembled from the parkingbrake lever. More particularly, as shown in FIG. 10j, there is provideda space 142 between the inner cable member 116 and the adjacent leversurface, thereby to permit the insertion of a suitable screwdriver, awlor the like to lift the inner cable member to the position of FIG. 10h,whereupon the inner cable member 116 may be laterally displaced from thelever 114, and may be longitudinally withdrawn from the brake assemblyvia the helical guide spring 120. During the assembly and disassembly ofthe apparatus, the ramp wall 114c is maintained spaced from theassociated surface of the brake shoe 116 by the extension 114f, as shownin phantom in FIG. 10a, whereby interference with the enlarged endportion 116a by the brake shoe 106 is avoided.

Referring now to the second embodiment of FIGS. 11-15, thegenerally-annular spring support portion 214a is defined by a pair ofcooperating semi-circular tab portions 214g and 214h, as in the previousembodiment. In order to limit the extent of travel of the helical guidespring 220 in the direction of the inclined ramp portion 214b, the arms214g and 214h are provided with radially inwardly directed stop tabs214i and 214j, respectively, as shown in FIG. 13. Thus, the stop tabslimit the extent of insertion of the srping 220, as shown in FIG. 15a.Referring to FIG. 15b, the ramp surface is inclined to the axis of thespring support portion 214a by the acute angle α", which ramp surface iscontained in a plane generally parallel with the longitudinal axis ofthe lever 214. As shown in FIGS. 15c-15j, in order to connect the innercable member 216 to the parking brake lever 214, the cable isprogressively introduced via the guide spring to cause the enlargedextremity 216a to ride up the inclined ramp surace 214c until theenlarged extremity rides over the upper edge of the inclined ramp wall214c (as shown in FIG. 15h), whereupon the inner cable member 216 isreceived by the slot 240, and the enlarged head portion 216a is 0eatedbehind the inclined ramp wall 214c, thereby to connect the inner cablemember 216 with the parking brake lever 214.

It will become apparent that the parking brake lever 214 is formed froma blank of flat metal stock by a minimum number of simple pressing andforming steps. Thus, the inclined wall 214c is deformed upwardly fromthe plane of the lever 214, whereupon the slot 240 is machined in theramp wall 214c to define the bifurcated portions 214m and 214n. Thespring support portion 214a is formed merely by bending upwardly in asemi-circular configuration the integral arm portions 214g and 214h.Thus, the parking brake lever is formed by a limited number ofmanufacturing operations, and at a minimal cost.

In accordance with another important feature of the invention, thehelical guide spring is provided with selected portions having tightlywound turns, thereby to improve the connection of the spring with thebacking plate and/or the parking brake lever. Referring to FIG. 16, itwill be noted that the spring 320 is provided with a bell-shapedenlarged portion 320a of tightly wound turns adjacent the backing plate302, thereby to limit the extent of travel of the spring outwardly ofthe backing plate. At its right hand end, the spring 320 extends withinthe spring support portion 214a of the parking brake lever 314.

In the modification of FIG. 17, the spring includes bell shaped portions420a and 420b spaced from the spring ends, thereby to limit the outwardextent of travel of the spring 420 relative to the backing plate 402,and the inward extent of travel of the spring relative to the springsupport portion 414a of the parking brake lever 414. Thus, the spring isaccurately positioned and maintained connected with the backing plate402 and the parking brake 414 when in the assembled condition of FIG.17.

Referring now to FIG. 18, the spring is provided at one end extremitywith a tightly wound portion 520a that extends within the backing plateopening, and at the other end the spring includes a tightly woundextremity 520b that extends within the generally annular spring supportportion 514a of a parking brake lever 514. Owing to the tightly woundturns of the portion 520a, lateral displacement of the spring relativeto the opening in the backing plate 502 is prevented, and at the otherend, the tightly wound spring portion 520b permits simple entry of thespring end within the annular spring support 514a.

In each of the spring embodiments, the spring extends to some extent atone end through the opening contained in the backing plate. Referring toFIGS. 19-21, the outer conduit member 617 is provided with aself-connecting fitting 650 as is known in the art, for example, asshown by the Gordy et al Reissue Patent No. 30,850. As shown in FIG. 20,the enlarged end extremity 616a of the inner cable member is introdcedinto the protruding end portion 620c of the spring 620, whereupon theparking brake conduit is progressively introduced until the fitting 650is snapped within the opening contained in the backing plate 602, asshown in FIG. 21. It will be noted that the spring 620 has beencompressed by the fitting 650 to the point that the bell-shaped portion620a and the end portion 620c of the spring 620 are now on the righthand side of the backing plate 620 of FIG. 21.

Consequently, the spring 620 has been changed from the non-compressedcondition of FIG. 20, to the compressed condition shown in FIG. 21,thereby bias the parking brake lever toward the brake release condition.

While in accordance with the Patent Statutes the preferred forms andembodiments of the invention have been illustrated and described above,it will become apparent that various changes can be made withoutdeviating from the previously set forth inventive concepts.

What is claimed is:
 1. A blind-cable type parking brake assembly foroperating brake shoe means relative to a brake surface associated with awheel of a vehicle, comprising:(a) a backing plate; (b) a parking brakelever mounted for pivotal movement relative to said backing plate, saidlever including spring support means adjacent one end thereof; (c) ahelical guide spring supported at one end by said spring support means,said spring extending, when in its initial normal non-compressedcondition, at its other end through, and terminating at an extremityarranged slightly beyond an opening contained in said backing plate,said spring including a bell-shaped portion of enlarged outer diameterhaving turns that are tightly wound relative to the remaining portion ofthe spring, said bell-shaped portion being in engagement with the sideof said backing plate adjacent said lever, thereby to limit the extentof longitudinal diplacement of said spring away from said lever; (d) acoaxial parking brake cable assembly including a flexible resilientinner cable member terminating at one end in an enlarged extremity; and(e) means connecting said inner cable member one end with said lever oneend, said lever one end including a ramp portion spaced from said springsupport means on the side thereof remote from said backing plateopening, said ramp portion having an inclined ramp surface facing saidspring support means, said ramp portion containing a cable mountingopening so arranged and of such a size and configuration that saidenlarged inner cable member extremity is operable for successiveintroduction through said spring, through said backing plate opening,and through said spring support means into sliding engagement with saidramp portion, whereby during the blind connection of said inner cablemember with said lever, the end portion of said inner cable memberinitially rides up said ramp portion and subsequently extends throughthe ramp opening for resilient return toward a connected position inwhich the inner cable member is retained in said mounting opening by theengagement of said enlarged extremity with the rear surface of said rampportion; (f) said parking brake assembly further including an outersleeve member (617), and self-connecting fitting means (650) mounted onsaid sleeve member for engaging said terminal spring portion to compresssaid spring longitudinally and for connecting said sleeve member withsaid backing plate opening.
 2. Apparatus as defined in claim 1, whereinsaid spring support means is generally annular; and further wherein saidspring includes a second tightly wound bell-shaped portion of enlargedouter diameter intermediate said spring support means and said backingplate, said second bell-shaped portion having a diameter greater thanthat of said annular spring support means and being arranged to abut andthereby limit the extent of longitudinal displacement of said springaway from said backing plate.
 3. A blind-cable type parking breakassembly for operating brake shoe means relative to a brake surfaceassociated with a wheel of a vehicle, comprising:(a) a backing plate(502); (b) a parking brake lever (514) mounted for pivotal movementrelative to said backing plate, said parking brake lever includingannular spring support means (514a) adjacent one end thereof; (c) ahelical guide spring (520) supported at one end by said spring supportmeans, said spring extending, when in its initial non-compressedcondition, at its other end through, and terminating at an end extremityarranged slightly beyond, and opening contained in said backing plate,the end portion (520a) of said spring other end from said springextremity to a point on the spring intermediate said backing plate andsaid lever being tightly wound relative to the center portion of thespring, thereby to prevent lateral displacement of said spring relativeto said backing plate; (d) a coaxial parking brake cable assemblyincluding a flexible resilient inner cable member terminating at one endin an enlarged extremity; and (e) means connecting said inner cablemember one end with said lever one end, said lever one end including aramp portion spaced from said spring support means on the side thereofremote from said backing plate opening, said ramp portion having aninclined ramp surface facing said spring support means, said rampportion containing a cable mounting opening so arranged and of such asize and configuration that said enlarged inner cable member extremityis operable for successive introduction through said spring, throughsaid backing plate opening and through said spring support means intosliding engagement with said ramp portion, whereby during the blindconnection of said inner cable member with said leve, the end portion ofsaid inner cable member initially rides up said ramp portion andsubsequently extends through the ramp opening for resilient returntoward a connected position in which the inner cable member is retainedin said mounting opening by the engagement of said enlarged extremitywith the rear surface of said ramp portion; (f) said coaxial parkingbrake cable assembly also including an outer sleeve member (617), andself-connecting fitting means (650) mounted on said sleeve member forengaging said spring extremity to compress said spring longitudinallyand for connecting said sleeve member with said backing plate opening.4. Apparatus as defined in claim 3, wherein said spring support means(514a) is annular, and further wherein said spring means terminates atsaid one end in a second tightly-wound portion (520b) that extendswithin said annular support means.